Apparatus for manufacturing molten irons to dry and convey iron ores and additives and manufacturing method using the same

ABSTRACT

The invention relates to an apparatus and method for manufacturing molten irons. The method for manufacturing molten irons includes providing a mixture containing iron by drying and mixing iron ores and additives, passing the mixture containing iron through one or more successively-connected fluidized beds to convert the mixture into a reducing material that is reduced and calcined, forming a coal packed bed, which is a heat source in which the reducing material has been melted, charging the reducing material to the coal packed bed and supplying oxygen to the coal packed bed to manufacture molten irons, and supplying reducing gas exhausted from the coal packed bed to the fluidized bed. In the providing a mixture containing iron, exhaust gas exhausted from the fluidized bed is branched to dry at least one of the iron ores and the additives. The apparatus for manufacturing molten irons uses this method for manufacturing molten irons. Through the use of the invention, at least one of iron ores and additives is dried and conveyed to thereby enhance energy efficiency and minimize the amount of required equipment.

BACKGROUND OF THE INVENTION

(a) Field of the Invention

The present invention relates to an apparatus and method formanufacturing molten irons, and more particularly, to an apparatus andmethod for manufacturing molten irons in which iron ores and additivesare dried while being conveyed, and then by the sensible heat of exhaustgas of a fluidized-bed reactors, the iron ores and additives are chargedto the fluidized-bed reactors to thereby manufacture molten irons.

(b) Description of the Related Art

The iron and steel industry is a core industry that supplies the basicmaterials needed in construction and in the manufacture of automobiles,ships, home appliances, and many of the other products we use. It isalso an industry with one of the longest histories that has progressedtogether with humanity. In an iron foundry, which plays a pivotal rollin the iron and steel industry, after molten irons (i.e., pig iron in amolten state) are produced using iron ores and coals as raw materials,steel is produced from the molten irons then supplied to customers.

Approximately 60% of the world's iron production is realized using theblast furnace method developed in the 14^(th) century. In the blastfurnace method, coke produced using as raw materials iron ores andbituminous coal that have undergone a sintering process are placed in ablast furnace, and oxygen is supplied to the furnace to reduce the ironores to iron to thereby manufacture molten irons. The blast furnacemethod, which is a main aspect of molten irons production, requires rawmaterials having a hardness of at least a predetermined level and grainsize that can ensure ventilation in the furnace. Coke in which aspecific raw coal that has undergone processing is needed as a carbonsource used as fuel and a reducing agent. Also, sintered ore that hasundergone a successive compacting process is needed as an iron source.Accordingly, in the modern blast furnace method, it is necessary toinclude raw material preparation and processing equipment such as cokemanufacturing equipment and sintering equipment. Therefore, not only isit necessary to obtain accessory equipment in addition to the blastfurnace, but equipment to prevent and minimize the generation ofpollution in the accessory equipment is needed. The amount ofinvestment, therefore, is considerable, ultimately increasingmanufacturing costs.

In order to solve these problems of the blast furnace method,significant effort is being put forth in iron foundries all over theworld to develop a smelting reduction process that produces molten ironsby directly using fine coal as fuel and a reducing agent, and alsodirectly using fine ores, which make up over 80% of the world's oreproduction, as an iron source.

The smelting reduction process typically uses a two-stage process ofpreliminary reduction and final reduction. The conventional molten ironmanufacturing apparatus includes a fluidized-bed reactor that formsfluidized beds, and a melter-gasifier that forms coal packed bed andthat is connected thereto. Iron ores and additives at room temperatureare charged in the fluidized-bed reactor to undergo preliminaryreduction. Since high-temperature reduced gas is supplied from themelter-gasifier to the fluidized-bed reactor, the iron ores andadditives increase in temperature as a result of making contact with thehigh-temperature reduced gas.

At the same time, 90% or more of the iron ores and additives at roomtemperature are reduced, and 30% or more of the same are calcined andcharged to the melter-gasifier.

Coal is supplied to the melter-gasifier to form a coal packed bed, andthe iron ores and additives at room temperature undergo smelting andslagging in the coal packed bed to be discharged as molten irons andslag. Oxygen is supplied through a plurality of tuyeres installed to anouter wall of the melter-gasifier such that the coal packed bed isburned and then the oxygen is converted into high temperature reducedgas, after which the high temperature reduced gas is supplied to thefluidized-bed reactor. Following reduction of the iron ores andadditives at room temperature, they are exhausted outside. A temperatureof the emitted exhaust gas is approximately 680° C., and a pressurethereof is 1.7˜2.5 bar.

In the case where iron ores are charged to the fluidized-bed reactor forreduction into reduced iron, in order to prevent the reduced iron fromsticking to the fluidized-bed reactor and in order to prevent thermalloss in the melter-gasifier, additives such as limestone and dolomiteare charged to the fluidized-bed reactor together with the iron ores.The additives are typically around 15˜20% of the total amount of thecharged material.

Prior to charging the iron ores and additives to the fluidized-bedreactor, the iron ores and additives are dried in a drying apparatus tothereby ensure the free flow of these materials in the fluidized-bedreactor. To perform this operation, hot air is supplied to the dryingapparatus to dry the iron ores and the additives. Since the iron oresmakes up 80% or more of the combination with the additives, overalloperating conditions are determined based on the requirements of theiron ore. However, because the additives have a grain size and densitythat are less than that of the iron ore, a significant amount of loss ofthe additives with a small grain size occurs if dried under the sameconditions as the iron ore. Further, the drying apparatus frequentlymalfunctions since a substantial load is given to the same in order torealize favorable drying. Finally, 50% or more of the iron ores becomefine ore of 1 mm or less to thereby clog the drying apparatus, therebynecessitating frequent production stoppages.

SUMMARY OF THE INVENTION

The present invention has been made in an effort to solve the aboveproblems. The present invention provides an apparatus and method formanufacturing molten irons in which exhaust gas of a fluidized-bedreactor is used as conveying gas for conveying iron ores and additives,and, at the same time, its sensible heat is used to dry the iron oresand the additives such that costs associated with drying are reduced.

A method for manufacturing molten irons includes the steps of providinga mixture containing iron by drying and mixing iron ores and additives;passing the mixture containing iron through one or moresuccessively-connected fluidized beds to convert the mixture into areducing material that is reduced and calcined; forming a coal packedbed, which is a heat source in which the reducing material has beenmelted; charging the reducing material to the coal packed bed andsupplying oxygen to the coal packed bed to manufacture molten irons; andsupplying reducing gas exhausted from the coal packed bed to thefluidized bed. In the step of providing a mixture containing iron,exhaust gas exhausted from the fluidized bed is branched to dry at leastone of the iron ores and the additives.

In the step of providing a mixture containing iron, at least one of theiron ores and the additives may be dried immediately prior to supply tothe fluidized bed.

The step of providing a mixture containing iron may include dischargingstored iron ores and additives; drying the iron ores and additives usingseparate heating air while vibrating the same; storing the dried ironores and additives; and supplying the stored iron ores and additives tothe fluidized bed.

Preferably, in the step of providing a mixture containing iron, anamount of branched exhaust gas is 20˜40% of an amount of exhaust gasexhausted from the fluidized bed.

Preferably, in the step of providing a mixture containing iron, at leastone of the iron ores and the additives is conveyed and simultaneouslydried.

Further, in the step of providing a mixture containing iron, a flow rateof exhaust gas is preferably 20˜30 m/s in the case where the iron oresare conveyed, and a flow rate of exhaust gas is preferably 10˜20 m/s inthe case where additives are conveyed.

Preferably, in the step of providing a mixture containing iron, the ironores are fine ores having a grain size of 8 mm or less.

The apparatus for manufacturing iron includes a conveying line fordrying and conveying iron ores and additives; one or more fluidized-bedreactors that reduce and calcine the iron ores and additives suppliedfrom the conveying line to perform conversion into reducing material; amelter-gasifier for charging the reducing material and receiving thesupply of oxygen to manufacture iron; a reducing gas supply line forsupplying reducing gas exhausted from the melter-gasifier to thefluidized-bed reactors; and a exhaust gas branch line for branchingexhaust gas exhausted from the fluidized-bed reactors and supplying thesame to the conveying line.

The apparatus may further include a hopper for each of the iron ores andthe additives; and a bypass line connected to the hoppers and supplyingthe iron ores and additives to the conveying line.

The apparatus may further include a drying assembly for drying the ironores and additives supplied to the hopper; a storage bin connected tothe drying assembly and for storing the dried iron ores and additive;and a conveyor belt connected to the storage bin and providing the ironores and additives to the fluidized-bed reactors.

Preferably, the conveying line is extended vertically, exhaust gas issupplied to a lower port of the conveying line, and the iron ores andadditives are supplied to the conveying line at a position 1˜2 m higherthan the supply position of the conveying line.

Preferably, a flow speed of the exhaust gas in the conveying line is10˜30 m/s.

Preferably, an amount of branched exhaust gas is 20˜40% of an amount ofexhaust gas exhausted from the fluidized-bed reactors.

Further, the iron ores are preferably fine ores having a grain size of 8mm or less.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of an apparatus for manufacturing moltenirons according to a first embodiment of the present invention.

FIG. 2 is a schematic view of an apparatus for manufacturing moltenirons according to a second embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will now be described indetail with reference to the accompanying drawings. It should be clearlyunderstood that many variations and/or modifications of the basicinventive concepts may appear to those skilled in the present art. Theembodiments are to be regarded as illustrative in nature, and notrestrictive.

FIG. 1 is a schematic view of an apparatus for manufacturing moltenirons according to an embodiment of the present invention. The apparatusdries and conveys iron ores and additives, and supplies the same to afluidized-bed reactor.

An apparatus 100 for manufacturing molten irons according to a firstembodiment of the present invention includes the main elements of afluidized-bed reactor unit 20, a melter-gasifier 10, a raw materialsupplying unit 60, and other accessory equipments. The fluidized-bedreactor unit 20 includes one or more fluidized-bed reactors having afluidized bed therein, and acts to reduce and calcine iron ores andadditives to reduced material. The reduced material is charged to themelter-gasifier 10, which includes a coal packed bed therein, and oxygenis supplied to the melter-gasifier 10 to thereby produced molten irons.Reduced gas exhausted from the melter-gasifier 10 is used to reduce andcalcine iron ores and additives through a fluidized-bed reactor, afterwhich the reduced gas is exhausted to the outside.

Elements included in the apparatus for manufacturing molten irons willnow be described in more detail.

The fluidized-bed reactor unit 20 includes a rock hopper 21 that ischarged with an iron-containing compound in which dry iron ores andadditives are mixed, and one or more fluidized-bed reactors having afluidized bed therein. An intermediate charge means is provided in therock hopper 21 shown in FIG. 1, and allows for iron ores and additivesto be charged to the fluidized-bed reactor that is maintained at apressure from a normal pressure to 1.5˜3.0 atmospheres.

The fluidized-bed reactors include a pre-heating reactor 23 forpre-heating the charged iron-containing compound, a preliminary reducingreactor 25 for performing preliminary reduction of the iron-containingcompound pre-heated in the pre-heating reactor 23, and a final reducingreactor 27 for performing final reduction of the iron-containingcompound that is reduced in the preliminary reducing reactor 25. In FIG.1, although the fluidized-bed reactors are shown to include threestages, such a configuration is for illustrative purposes and thepresent invention is not limited in this regard. Accordingly, a varietyof different numbers of stages may be used for the fluidized-bedreactors. The iron ores and additives supplied to the fluidized-bedreactors forming a fluidized bed by contacting a high temperaturereduced gas current therewith, and it is converted into a hightemperature reduced material that is at a temperature of 80° C. or more,is 80% or more reduced, and is 30% or more calcined.

Although not shown in FIG. 1, to prevent scattering loss when reducedmaterial discharged from the fluidized-bed reactors is directly chargedto the melter-gasifier 10, a hot compacting apparatus may be mountedbetween these elements. Further, a hot intermediate vessel 12 isprovided for supplying the reduced material discharged from thefluidized-bed reactors to the melter-gasifier 10 to thereby make supplyof the reduced material to the melter-gasifier 10 easy.

Lump coal or shaped coal realized by pressing fine coal is supplied tothe melter-gasifier 10 to form a coal packed bed. The lump coal orshaped coal supplied to the melter-gasifier 10 is gasified by apyrolysis reaction at an upper area of the coal packed bed and by acombustion reaction by oxygen at a lower area of the coal packed bed.Hot reduced gas generated in the melter-gasifier 10 by the gasifiedreaction is supplied in succession to the fluidized-bed reactors througha reduced gas supply line L59, which is connected to a rear end of thefinal reducing reactor 27, to be used as a reducing agent and fluidizedgas.

A dome-shaped empty space is formed to an area above a coal packed bedof the melter-gasifier 10. The flow rate of gas is reduced by the emptyspace such that large amounts of fine powder included in the chargedreduced material and fine powder generated as a result of an abruptincrease in temperature of coal charged in the melter-gasifier 10 areprevented from being discharged out of the melter-gasifier 10. Further,such a configuration allows for absorbing of variations in pressure inthe melter-gasifier 10 caused by irregular changes in the amount of gasgenerated as a result of directly using coal. The coal is gasified andremoves volatile members therein while dropping to the bottom of thecoal packed bed, and is ultimately burned as a result of oxygen suppliedthrough tuyeres at the bottom of the melter-gasifier. The generatedcombustion gas raises through the coal packed bed, and is converted intohigh temperature reduced gas and exhausted to outside themelter-gasifier 10. Part of the combustion gas is scrubbed and cooledwhile passing through water collecting devices 51 and 53 such thatpressure applied to the melter-gasifier 10 is maintained within therange of 3.0˜3.5 atmospheres.

A cyclone 14 collects exhaust gas generated in the melter-gasifier 10such that dust is again supplied to the melter-gasifier 10, and gas issupplied as reduced gas to the fluidized-bed reactors through thereduced gas supply line L59.

Reduced iron drops to the bottom of the coal packed bed together withthe coal to undergo final reduction and smelting by combustion gas andcombustion heat generated by gasifying and combusting coal, after whichthe iron is exhausted to the outside.

The raw material supplying unit 60 that uses the exhaust gas exhaustedfrom the fluidized-bed reactors includes an iron ore hopper 30, anadditive hopper 40, and a conveying line L57, and acts to dry and conveyiron ores and additives to the fluidized-bed reactor unit 20. Iron oresand additives discharged respectively from the iron ore hopper 30 andthe additive hopper 40 are supplied to the rock hopper 21 through theconveying line L57 connected to an iron ores supply line L30 and anadditive supply line L40. Among the fluidized-bed reactors, part of theexhaust gas exhausted from the pre-heating reactor 23 is supplied to theconveying line L57 through a branched exhaust gas branched line L55. Theconveying line L57 is extended vertically, and iron ores and additivesare supplied to the conveying line L57 at a location 1˜2 m higher thanthe supply position of exhaust gas. If iron ores and additives aresupplied from a location 1˜2 m higher than the supply position ofexhaust gas, scattering loss of the iron ores and additives occurringduring drying and conveying is minimized, and the area of contact withthe exhaust gas is maximized such that it is possible to dry and conveythe iron ores and additives very efficiently. The supply position of theiron ores and additives from the conveying line L57 shown in FIG. 1 isused for illustrative purposes and does not restrict the presentinvention. Accordingly, it is only necessary that the conditionsdescribed above be satisfied.

Iron ores and additives are dried and conveyed by the exhaust gasexiting the exhaust gas branched line L55 that is connected to the lowerport of the conveying line L57 to be charged in the rock hopper 21. Theamount of exhaust gas branched and used in drying and conveying ispreferably 20˜40% of the exhaust gas amount exhausted from thefluidized-bed reactors. If this amount of exhaust gas is used, an amountof dried and conveyed iron ores and additives is sufficient tomanufacture molten irons.

If iron ores having a grain size of 8 mm or less is used, volume anddensity are relatively low such that a smooth supply to the rock hopper21 is possible. Further, a suitable flow speed of the exhaust gas in theconveying line L57 is 10˜30 m/s. If the flow speed of the exhaust gas isless than 10 m/s, the pressure at the bottom part of the conveying lineL57 increases to destabilize the flow of the exhaust gas. On the otherhand, if the flow of the exhaust gas exceeds 30 m/s, scattering loss mayoccur.

Hence, by using the exhaust gas as a conveying gas of the iron ores andadditives and drying the same by the sensible heat of the exhaust gas,the exhaust gas may be recycled to thereby save energy, and drying maybe stably realized. Since drying and conveying occur simultaneously inthe conveying line L57, the number of different types of equipment usedfor drying and conveying is significantly reduced. Especially, theamount of iron ores and additives supplied to the conveying line L57 maybe adjusted respectively by an iron ore valve V30 and an additive valveV40, and the amount of the exhaust gas supplied to the conveying lineL57 may be adjusted by an exhaust gas valve V55.

In the apparatus for manufacturing molten irons according to the firstembodiment of the present invention, iron ores and additives areselectively supplied to the conveying line L57 according to operatingconditions to thereby realize drying and conveying. In the case whereadditives are supplied to the conveying line L57 to realize drying andconveying, the valve V40 is opened while the valve V30 is closed suchthat only the additives are dried and conveyed. In this case, the flowspeed of the exhaust gas supplied to the conveying line L57 ispreferably 10˜20 m/s. If the flow speed of the exhaust gas is less than10 m/s, additives charged to a lower part of the conveying line L57 arenot fully transported in the conveying line L57, and some particles areaccumulated in the lower part of the conveying line L57. Therefore, apressure at the lower part of the conveying line L57 is significantlyincreased such that flow in the conveying line L57 is made unstable. Onthe other hand, a flow speed of the exhaust gas exceeding 20 m/s is notsuitable since the grain size of the additives is too small. Here, theamount of iron ores that is processed is approximately 100˜130 tons/day,and the amount of additives processed is approximately 15˜30 tons/day.

Further, in the case where iron ores are supplied to the conveying lineL57 to be dried and conveyed, the valve V30 is opened while the valveV40 is closed such that only the iron ores are dried and conveyed. Inthis case, the flow speed of the exhaust gas supplied to the conveyingline L57 is preferably slightly greater. As a result of the greaterparticle size and density of the iron ores compared to the additives,the flow speed of the exhaust gas is preferably 20˜30 m/s. As describedabove, the iron ores and additives may be separately dried and conveyedas in the first embodiment of the present invention, or may be mixedthen dried and conveyed.

FIG. 2 is a schematic view of an apparatus for manufacturing moltenirons according to a second embodiment of the present invention.

An apparatus 200 for manufacturing molten irons according to the secondembodiment of the present invention shown in FIG. 2 is identical to thatof the first embodiment except for a raw material supply unit 65.Accordingly, elements of the apparatus 200 for manufacturing moltenirons identical to the elements of the first embodiment will not bedescribed, and the explanation will be concentrated on the raw materialsupply unit 65.

As shown in FIG. 2, the raw material supply unit 65 includes the ironore hopper 30, the additive hopper 40, a drying assembly 61, an iron orestorage bin 34, an additive storage bin 44, and conveyor belts 63 and65.

An iron ore supply line L31 connected to the iron ore hopper 30 and anadditive supply line L41 connected to the additive hopper 40 areconnected to the drying assembly 61 to supply iron ores and additivesthereto. The drying assembly 61 supplies hot air to a lower area of itsdispersing plate such that iron ores and additives are dried while beingvibrated to a fluidized bed state. Iron ores and additives dried in thedrying assembly 61 are stored respectively in the iron ore storage bin34 and the additive storage bin 44. The dried and stored iron ores andadditives are transmitted by the first conveyor belt 63. The firstconveyor belt 63 is is connected to the vertical second conveyor belt 65such that the dried iron ores and additives are charged to the rockhopper 21.

The second embodiment of the present invention is used by connecting theconveying line L57 to the above apparatus. Iron ores are supplied to theconveying line L57 through an iron ore bypass line L33 connected to theiron ore supply line L31, and additives are supplied to the conveyingline L57 through an additive bypass line L43 connected to the additivesupply line L41. Accordingly, iron ores and additives are formed into aniron-containing mixture and dried immediately prior to supply to thefluidized-bed reactors having fluidized beds.

Especially, the apparatus 200 for manufacturing molten irons of thesecond embodiment provides particular convenience by using the bypasslines L33 and L43 when the drying assembly 61 malfunctions or anexcessive load is given to the drying assembly 61.

That is, in the case where the drying assembly 61 malfunctions, valvesV31 and V41 directed to the drying assembly 61 are closed, while valvesL33 and L43 respectively mounted on the bypass lines L33 and L43 areopened such that iron ores and additives are directly supplied to theconveying line L57. Further, the valve V55 is opened such that exhaustgas is supplied to the conveying line L57 through the exhaust gasbranched line L55, resulting in drying and conveying iron ores andadditives to the rock hopper 21. Accordingly, iron ores and additivesare continuously dried and conveyed to enable charging to thefluidized-bed reactors, thereby allowing the manufacture of molten ironsto be more flexibly performed.

In the case where a significant load is applied to the drying assembly61, the valves V33 and V43 are opened in a state where both the valvesV31 and V41 directed to the drying assembly 61 are opened such that partof the iron ores and additives supplied to the drying assembly 61 aresupplied to the conveying line L57.

Therefore, the load applied to the drying assembly 61 is minimized.

The present invention will be described in greater detail below throughan experimental example. This experimental example merely illustratesthe present invention and is not meant to limit the present invention.

EXPERIMENTAL EXAMPLE

Iron ores and additives of limestone were dried and conveyed through aconveying line. The properties of the iron ores and additives used inthis case are as shown in Table 1 below. TABLE 1 Iron Ores Additives(Limestone) Composition T. Fe 63.43 wt % CaO 50.67 wt % FeO 0.24 wt %MgO 2.44 wt % SiO₂ 3.41 wt % SiO₂ 1.48 wt % Al₂O₃ 2.04 wt % Watercontent 5˜10 wt % 5 wt % or less Grain size distribution 8 mm or less 4mm or less

Among the exhaust gas exhausted from the fluidized-bed reactors, 20˜40%was branched and supplied to the conveying line. The details of theexhaust gas supplied to the conveying line are as shown in Table 2below. TABLE 2 Composition CO 20 vol %, H₂ 21 vol %, CO₂ 20 vol %, N₂ 39vol % Temperature and Pressure 680° C., 1.7˜20.0 kgf/cm² Flow rate8000˜9000 Nm³/hr

In the case where iron ores and the additives of limestone are eachsupplied to the conveying line, the size of the conveying line extendedvertically, and the gas flow rate and pressure drops in the conveyingline are as shown in Table 3 below. TABLE 3 Inner Diameter 0.2 m, SizeHeight 40.0 m Iron Ores Gas flow rate 20˜30 m/s Pressure drop 0.30˜0.50kgf/cm² Additives Gas flow rate 10˜20 m/s Pressure drop 0.05˜0.2 kgf/cm²

Results of comparing water content prior to drying and following dryingand conveying of the iron ores and additives in the conveying line areshown in Table 4 below. TABLE 4 Iron Ores Additives (Limestone) Processrate 100˜130 tons/day 15˜30 tons/day Water content 5˜10 wt % 5˜6 wt %prior to drying Water content 3 wt % or less 1 wt % or less followingdrying

As shown in Table 4, when the iron ores and additives are dried throughthe conveying line, the amount of water content therein is significantlyreduced, thereby indicating that conveying and drying are efficientlyrealized.

The present invention has the advantage of being able to use fine oresand fine additives. That is, by using iron ores and additives of aminimal grain size, these materials may be conveyed and simultaneouslydried using exhaust gas.

In the present invention, since exhaust gas emitted from fluidized bedsare branched and used, the amount of waste gas is reduced and energy maybe reused.

In particular, by drying the iron ores and additives immediately priorto supplying the same to fluidized beds, pre-heating and reduction ratesin the fluidized beds are further increased.

Also, since the present invention may be applied to general dryingassemblies, precautions may be taken against any problems that may occurwith the drying assembly and load applied to the drying assembly may bedispersed such that the apparatus for manufacturing molten irons may bemore flexibly operated.

A mixture containing iron is reduced using multiple stages of fluidizedbeds such that a reduction material that has been fully reduced andcalcined may be obtained.

Although embodiments of the present invention have been described indetail hereinabove in connection with certain exemplary embodiments, itshould be understood that the invention is not limited to the disclosedexemplary embodiments, but, on the contrary is intended to cover variousmodifications and/or equivalent arrangements included within the spiritand scope of the present invention, as defined in the appended claims.

1. A method for manufacturing molten irons, comprising the steps of:providing a mixture containing iron by drying and mixing iron ores andadditives; passing the mixture containing iron through one or moresuccessively-connected fluidized beds to convert the mixture into areducing material that is reduced and calcined; forming a coal packedbed, which is a heat source in which the reducing material has beenmelted; charging the reducing material to the coal packed bed andsupplying oxygen to the fluidized bed to manufacture molten irons;supplying reducing gas exhausted from the coal packed bed to thefluidized bed; and in the step of providing a mixture containing iron,branching exhaust gas exhausted from the fluidized bed to dry at leastone of the iron ores and the additives.
 2. The method of claim 1,comprising in the step of providing a mixture containing iron, drying atleast one of the iron ores and the additives is immediately prior topassing the mixture to the fluidized bed.
 3. The method of claim 2,wherein the step of providing a mixture containing iron comprises thestep of: discharging stored iron ores and additives; drying the ironores and additives using separate heating air while vibrating the ironores and additives; storing the dried iron ores and additives; andsupplying the stored iron ores and additives to the fluidized bed. 4.The method of claim 1, comprising, in the step of providing a mixturecontaining iron, branching 20˜40% of an amount of exhaust gas exhaustedfrom the fluidized bed.
 5. The method of claim 1, comprising in the stepof providing a mixture containing iron, conveying and simultaneouslydrying at least one of the iron ores and the additives.
 6. The method ofclaim 5, wherein in the step of providing a mixture containing iron, theiron ores are conveyed and a flow rate of the exhaust gas is 20˜30 m/s.7. The method of claim 5, wherein in the step of providing a mixturecontaining iron, the additives are conveyed and a flow rate of theexhaust gas is 10˜20 m/s.
 8. The method of claim 1, wherein in the stepof providing a mixture containing iron, the iron ores are fine oreshaving a grain size of 8 mm or less.
 9. An apparatus for manufacturingmolten irons, comprising: a conveying line for drying and conveying ironores and additives; one or more fluidized-bed reactors that reduce andcalcine the iron ores and the additives supplied from the conveying lineto perform conversion into reducing material; a melter-gasifier forcharging the reducing material and receiving the supply of oxygen tomanufacture molten irons; a reducing gas supply line for supplyingreducing gas exhausted from the melter-gasifier to the fluidized-bedreactors; and an exhaust gas branch line for branching exhaust gasexhausted from the fluidized-bed reactors and supplying the exhaust gasto the conveying line.
 10. The apparatus of claim 9, further comprising:a hopper for each of the iron ores and the additives; and a bypass lineconnected to the hoppers and supplying the iron ores and additives tothe conveying line.
 11. The apparatus of claim 10, further comprising: adrying assembly for drying the iron ores and additives supplied to thehopper; a storage bin connected to the drying assembly and for storingthe dried iron ores and additives; and a conveyor belt connected to thestorage bin and providing the iron ores and additives to thefluidized-bed reactors.
 12. The apparatus of claim 9, wherein theconveying line is extends vertically, exhaust gas is supplied to a lowerport of the conveying line, and the iron ores and additives are suppliedto the conveying line at a position 1□2 m higher than the supplyposition of exhaust gas.
 13. The apparatus of claim 9, wherein a flowspeed of the exhaust gas in the conveying line is 10˜30 m/s.
 14. Theapparatus of claim 9, wherein an amount of branched exhaust gas is20˜40% of an amount of exhaust gas exhausted from the fluidized-bedreactors.
 15. The apparatus of claim 9, wherein the iron ores are fineores having a grain size of 8 mm or less.